Correlation of duodenal histology with tissue transglutaminase and endomysial antibody levels in pediatric celiac disease.

BACKGROUND & AIMS: IgA antibodies against tissue transglutaminase (TTGA) and endomysium (EMA) are sensitive and specific markers for celiac disease (CD). Data correlating TTGA and EMA levels with degree of villous atrophy are limited. We compared duodenal histopathology in pediatric CD patients with TTGA and EMA serologies, symptoms, height, and weight. METHODS: We identified 117 pediatric patients retrospectively who had serologic testing for IgA TTGA and IgA EMA and duodenal biopsies graded by modified Marsh criteria as 0-3c. Data were analyzed with Spearman rank correlation and multinomial logistic regression. RESULTS: IgA TTGA (r = .704, P < .001) and IgA EMA (r = 0.740, P < .001) correlated with intestinal villous atrophy in pediatric CD patients by Spearman rank correlation. Similar correlations were found in a subset of 23 patients younger than 3 years of age. Multinomial logistic regression revealed increased probability of Marsh 3a or greater changes with increasing TTGA or EMA levels. Strongly positive antibody levels (TTGA >100 units or EMA titer >1:1280) were highly specific (>98%) for Marsh 3a or greater lesions. Among symptoms, abdominal distention and diarrhea were associated with abnormal histology. CONCLUSIONS: IgA TTGA and EMA levels correlate with duodenal villous atrophy in pediatric CD patients. IgA TTGA >100 or EMA >1:1280 were nearly always associated with CD histopathology. With further validation of this observation, strongly positive titers might be considered sufficient for diagnosis of pediatric patients at risk for CD. Symptoms, height, and weight are not reliable predictors of CD.

Opening of ATP-sensitive potassium channels causes generation of free radicals in vascular smooth muscle cells.

Recent evidence suggests that opening of mitochondrial K(ATP) channels in cardiac muscle triggers the preconditioning phenomenon through free radical production. The present study tested the effects of K(ATP) channel openers in a vascular smooth muscle cell model using the fluorescent probe MitoTracker (MTR) Red trade mark for detection of reactive oxygen species (ROS). Rat aortic smooth muscle cells (A7r5) were incubated with 1 micro M reduced MTR (non-fluorescent) and the MTR oxidation product (fluorescent) was quantified. Thirty-minute pretreatment with either diazoxide (200 micro M) or pinacidil (100 micro M), both potent mitochondrial K(ATP) channel openers, increased fluorescent intensity (FI) to 149 and 162 % of control (p < 0.05 for both), respectively, and the K(ATP) channel inhibitor 5-hydroxydecanoate (5 HD) blocked it. Valinomycin, a potassium-selective ionophore, raised FI to 156 % of control (p <: 0.05). However, 5 HD did not affect the valinomycin-induced increase in FI. Inhibition of mitochondrial electron transport (myxothiazol) or uncoupling of oxidative phosphorylation (dinitrophenol) also blocked either valinomycin- or diazoxide-induced increase in FI, and free radical scavengers prevented any diazoxide-mediated increase in fluorescence. Finally the diazoxide-induced increase in fluorescence was not blocked by the PKC inhibitor chelerythrine, but was by HMR 1883, a putative surface K(ATP) channel blocker. Thus opening of K(ATP) channels increases generation of ROS via the mitochondrial electron transport chain in vascular smooth muscle cells. Furthermore, a potassium-selective ionophore can mimic the effect of putative mitochondrial KATP channel openers. We conclude that potassium movement through KATP directly leads to ROS production by the mitochondria.